Gun mount adapter



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GUN MOUNT AD'APTER lll/,I4 L 7'5 Filed Nov. 14, 1959 w. Q. McNExLL fr AL.

W. G. MCNEILL HAL.

GUN MOUNT ADAPTER Filed Nov. 14, 1939 www. NW. Ww

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22eme MCNEILL. Ets-AL GUN MOUNT ADAPTER y Filed Novv.' 14, 1939 5 sheets-shew .4 j

ug. 18, 942. G. MCNILL ET-AL 22935069 x GUN MOUNT ADAPTER Filed Nav. .14, 1939 '5 sheets-sheet 5f 07 Z0 be /03 Joa Arran/ver:

` of 1921 or the M2 model.

Patented Aug. 18, 1942 GUN MOUNT ADAPTER Walter G. McNeill and Irwin G. Boehm, Dayton, Ohio Application November 14, 1939, Serial No. 304,440

8' Claims. (Cl. 89-44) (Granted under the act of March 3, 1883. as amended April 30, 1928; 370 0. G. 757) The invention described herein may be manufactured and used by or for the Goverment for governmental purposes. without the-payment to us of any royalty thereon.

'I'he subject of this invention is a cradle in which a rapid firing automatic machine gun may be floatingly mounted. 'I'he invention is speciiically adapted to be used in connection with a 50 caliber Browning aircraft machine gun, model 'Ihe invention is also adapted to be used with the 30 caliber Browning aircraft machine gun, although it is to be understood that the invention is broadly applicable.

It is well established that a rapid firing machine gun, of the aircraft type mounted to be manipulated and trained by hand, is diicult if not impossible to hold in the aimed position during firing, the oscillations and vibrations of the gun being such that it is generally only possible after one or two shots to fire in the general direction of the target.

An object of this invention is to provide novel recoil and counterrecoil absorbing means adapted and arranged to control the oscillations and vibrations of the gun during rng to such an extent that the gun may be maneuvered by hand and accurately fired from a yoke mount of the type commonly used for mounting machine guns in airplanes.

It is another object of this invention to provide an improved cradle in which the gun may be mounted for small amounts of training movement independent of the cradle.

It is still another object of this invention to provide a spring actuated mechanism for returning the cradle and gun to normal position from an external downward trained position and mechanism for holding the gun in a selected position.

In the drawings:

Figure 1 is a top plan view showing the machine gun in a cradle mount constructed in accordance with the teaching of the invention in which the recoil and counterrecoil absorbing means is arranged between the rear of the gun and the cradle.

Figure 1a shows a modification of the front of the cradle in which the bearing sleeve is split for convenience of assembly.

Figure 2 is a side elevational view of the device as shown in Figure 1.

Figure 3 is a cross-section along the lines 3-3 of Figure 1 showing the vibration absorbing mechanism in detail.

Figure 4 is a cross-section along the lines 4-4 of Figure 1.

Figure 5 is a second embodiment of the invention in which recoil springs only are mounted at the front and rear of the gun, thecounterrecoil springs being omitted.

Figure 6 is a side elevational view of Figure 5. Figure 7 is a cross-section along the lines 1-1 of Figure 6.

Figure 8 is a front elevational mount shown in Figure 5.

Figure 9 is a top plan view of a third embodiview of the ment of the invention in which the recoil springV is mounted between the rear of the gun and-the cradle and the counterrecoil spring is mounted between the front of the gun and the cradle.

Figure 10 is a cross-sectional view along the lines lll-I0 of Figure 9.

Figure 11 is a cross-sectional view along the lines I I-II of Figure 9.

Figure 12 is a top plan view of still another embodiment of the invention.

Figure 13 is a side elevational view of Figure 12.

Figure 14 is a top plan view of a fourth embodiment of the invention using three recoil and a single counterrecoil spring.

Figure 15 is a side elevational view of the de-4 vice in Figure 14.

Figure 16 is a sectional view along the line lli-I6 of Figure 18.

Figure 17 is a cross-sectional view taken the lines I'I-II of Figures 14 and 19.

Figure 18 is an end elevational view of Figure 15.

Figure 19 is a cross-sectional view taken along lines I9-l9 of Figure 15.

Figure 20 is a cross-sectional view taken alog lines 2li-20 of Figure 18.

Fig. 21 is a cross-sectional view along the lines 2|-2l of Fig, 14.

Fig. 22 is a cross-sectional view along the lines 22-22 of Fig. 14.

Referring to the drawings in detail and particularly to the preferred embodiment of the Vinvention illustrated in Figures l through 4, I represents a rapid firing machine gun of the Browning aircraft type iloatingly mounted in a cradle formed of side plates 2 mounted on trunnions 3 to pivot about a horizontal axis. Trunnions 3 are carried by yoke 4, having a portion 5 adapted to t in a suitable vertical bearing in support 6. At the front end of the cradle and integral with side plates 2 is a bearing sleeve 1 in which the front end of the gun is mounted for sliding movement. The bearing may be made in any suitable manner and for lconvenience of assembly may be along '55 made, as shown in Figure la', of two halves, la

.in the and 1b, bolted together. Each half is integral with a side plate 2. To prevent undesirable wear on the barrel cooling sleeve 8a bearing 9 may be fastened to the cooling sleeve to slide in bearing sleeve 1. y

The standardback plate of the machine gunis,

a special back plug I2vand bearing plate I4.

The Browning 50 caliber aircraft gun, for which this mount is particularly adapted, has .a trunnion reaction of approximately nine thousand pounds. In order to effectively absorb an amount of this reaction which will 'permit manual handling of the gun on a trunnion support during periods of sustained firing, it is necessary to select a recoil absorbing means which will absorb the greatest possible portion of the trunnion reaction and at least partially return to normal position in the interval of time between the firing of successive shots. In the preferred embodiment of the invention, springs are the recoil and counterrecoil forces. In order to properly function, the spring must be capable of absorbing the recoil energy without acquiring a used to absorb set under repeated operation. A spring could be selected, when firing single shots, which would absorb practically all the recoil energy and transmit a relatively small force to the cradle. The time required for absorbing practically all the recoil energy is greater than if part of the recoil energy is absorbed and part is transmitted to the cradle support. A stii spring will absorb less and transmit more of the recoil energy to the cradle support than a soft spring. A soft spring having a relatively large capacity for absorbing recoil energy will necessarily require more time to receive the load and return to normal position than a stiiIer spring. It is desirable to use a spring having the greatest possible energy absorbing characteristics and yet will absorb the energy and return to normal position allotted time interval. It has been found that by pre-compressing the recoil and counterrecoil springs, a relatively soft spring can be used which will give the desired results of a spring having a high capacity for absorbing energy and yet willabsorb and trasmit the energy and return to approximately normal position in the firing interval. Referring to Figures l and 3, springs I1 and I8 are compressed, in the case of a 50 caliber machine gun, approximately three-quarters of an inch each by screwing in plug I2 until springs I1 and I8 are pre-loaded approximately four hundred and eighty pounds. For a 30 caliber gun,vthe amount of pre-compression may be determined by trial until the desired result is obtained or it may be determined by measuring the recoil of a rloatingly mounted gun of a given caliber and pre-loading the springs for that given caliber by an amount equal to the measured recoil.

Upon firing, the gun recoils approximately W10" for the first shot and returns approximately W10" before the next shot is red. `Upon firing the secon'd shot, the gun recoils approximately 1%0 and returns the same amount. The movement for continuous tiring is then approximately 3A0" in each direction. There is comparatively little jar transmitted to the operator through the training grips compared to apparatus not using the vibration absorbing means. The maneuverability of the gun as well as theaccuracy of fire are materially improved.

Again referring to Figures 1 to 4 of the drawings, the back plate assembly comprising the back lug I2, bearing sleeve Il and I8, is removable as a plate I0, extension II, and I4 and springs I1 unit by removing bolts I5 and I6, operating conventional back plate latch 22 and sliding the back plate vertically out of locking engagement with the machine gun in a well-known manner. This arrangement permits ready disassembly and allows the adjusted pre-compression setting on the springs to be retained. An opening 23 in plug I2 permits access to conventional buier 24 for adjustment thereof. Suitable openings I5 are provided in the side plates 2 to permit connection of the operating means for the ring mechanism. The firing mechanism operating means, illustrated in Figure l, as a sear operating solenoid 25 controlled by a trigger switch 20. It is obvious that a suitable hand operated linkage system may be used to operate the sear mechanism of the gun. The gun is maneuvered and pointed by means of hand grips` 2I integral with the side plates 2. In this construction, the hand grips are located farther to the rear than ordinarily, resulting in an increased leverage which facilitates handling of the gun. The recoil and counterrecoil springsl are mounted coaxial with the gun, or in other words the center line of the springs is coincidental with a line longitudinal of the gun and through its center of gravity which may or may not lie on the center line of the barrel of the gun,

Second embodiment In the embodiment shown in Figures 5 through 8, the cradle is similar to the cradle shown in Figures 1 through 4, and comprises side plates 2a pivoted to yoke 4a by means of trunnions 3a. The cradle is provided with bearings 26 and 21 integral therewith for slidably receiving the gun Ia. Bracket 2 8 suitably bolted to the rear of the gun at 30 has integral therewith extension memberr 29 slidably received in bearing 26. Bearing 21 slidably receives the front portion of the gun, the bearing being in this instance the conventional barrel cooling sleeve 34 in which the recoiling barrel reciprocates during operation of the gun. It-is to be understood that a bearing could be fastened to the cooling sleeve 34 to slide in bearing sleeve 21 if desired. Bracket 3I is suitably bolted to the gun at 32 and 33 and receives recoil spring 36 between end 31 of the bracket and projection 38 on the cradle. A second recoil spring 39 is received between bracket 28 and rim 48 on the end of the cradle. In this embodiment no counterrecoil springs are provided. Springs 36 and 39 are suitably precompressed, for instance, by pressing bracket 3| in place against the action of the springs prior to bolting it to the gun. The tension in the springs lused than` in the embodiment in Figures l through 4.

Third embodiment -In the embodiment of the invention shown in Figures 9 through '11, side plates 2b are mounted on yoke 4b by trunnion connections 3b. United with the front end of the cradle is bearing sleeve 4| for slidably receiving bearing 42 fastened to gun lb by means of bracket 43, which in turn is bolted to the gun at 44 and 45. A counter recoil spring 46 is received between bracket 43 andend 41 ofcradle 2b. An extension bracket 48 is suitably fastened to the rear of the gun at 49 and 50 and has integral therewith extension 5| 'slidably received in bearing 52 carried by flange 53 which in turn is bolted to side plates 2b by bolts 54 and 55. Recoil spring 56 is received between bracket 48 and flange 53. Springs 46 and 56 are precompressed a predetermined amount in assembled condition in Figure 9 by pressing in flange 53 to line up the openings in the flange and the side plates and passing bolts 54 and 55 therethrough. The tension in the springs may be adjusted in any well-known manner, such as for example, by placing spacer elements such as washers or the like, between the springs and the brackets. By having the counterrecoil spring be'tween the front end of the gun and the cradle, the rear of the cradle may be shortened, leaving more room in the gunners compartment for the gunner.

Fourth embodiment In the embodiment illustrated in Figures `l? and 13, the side plates 2c are mounted on yoke 4c by means of trunnion connections 3c. Bolts 59 and 60, spaced to engage conventional fastening lugs (not shown) on the machine gun for mounting the same, are each fioatingly mounted in side plates 2c by means of brackets 6|. Since the brackets are identical, only one will be described. Bracket 6| isl slidably received in an openingg62 in side plate 2c. Rods 64, integrally united with bracket 6| are slidably received in lugs 65 integral with side plates 2`c. Opposed precompressed springs 63 surround rods 64 and abut bracket 6| and lugs 65. The tension in the springs may be adjusted in any well-known manner, such as for example, placing spacer elements such as washers or the like between the springs and the brackets or lugs. While the lugs 65 are shown as being welded to the side plates, it is to be understood that they may be fastened thereto by means of rivets, bolts or the like. This embodiment of the invention is a convenient one for readily attaching and detaching the gun since bolts 59 and 60 are spaced to pass through the conventional fastening lugs on the machine gun. Also this cradle is somewhat shorter than any one of the prior three embodiments.

Fifth embodiment The embodiment of the cradle shown in Fig*- ures 14 through 2O is substantially the same as in Figures 12 and 13, except that a single counterrecoil spring 681s used in conjunction with a plurality of recoil springs 69, and 1|.

Figures 14 through 20 also show a cradle and a mount therefor, in which the cradle may be moved independently of the mount. There is further provided spring means for returning the cradle and gun to normal position after having been trained downwardly. The gun is attached to the cradle by bolts 66 and 61 which pass through conventional fastening lugs on the gun.

Bolt 66 passes through member |50 and plate |5I, located on the outside of frame 2d. Bolt 66 75 bracket 90 by bolt 96 and to arm 16 by bolt 91.

also passes through another plate (not shown)l similar to |5| but located on the opposite side of frame 2d. These plates aid in guiding member 50 in its reciprocatory movement. Projecting from member |50 is a member |52 slidably received in a cutout portion in bracket |53. (See Fig. 22.) Plate-like member |54, integral with members |50 and |52 is slidably supportedby bracket |55 and the non-cutaway portions of upper part of bracket |58. Rods |56 and |51 are xedly received in openings in member |52 and are slidably received in openings in the upstanding leg of brack |55. Buckling of the coil springs is prevented by rods |56 and |51.

Bolt 81 passes through member |60 and guide plates |6| and |62. Plate-like members |63 and |64 project from member |60 and slide upon brackets |65, |66. |61 and |68. Spring-guiding rods |69 and |10 are xedly received in portions |1| and |12, respectively, which in turn are integral with plates |63 and |64 and member |66. Portions |1| and |12 are slidably received in cut-out portions in supporting brackets |66 and |61. Rods |69 and |10 are slidably supported at their outer ends by being received in openings in brackets |65 and |66. (See Fig. 2'1.)v

The cradle in this embodiment is connected to and suspended from the gun mount by brackets 13 and 14. Because the right and left sides of the mount are identical, only one side will be shown and vdescribed in detail. Bracket 14 is pivotally connected to arm 16 of the mount by bolt 12. As vshown in Figure 19, gear segments 11 and 'I6 are welded to side plates 2d. Gear segment 18 is received in a cut-out portion 19 in bracket 14. Relative movement between bracket 14 and segment 18 is controlled by pin 80 carried by bracket 14 received in slot 8| in gear segment 18. Gear segment 82, pivotally carried by bracket 14, meshes with the gear segment 18 to control relaf tive lateral movement of the cradle in the mount.

Link 63 is`non-rotatably connected to gear segment 82 by the square opening in the gear segment fitting over a square portion on bolt 84,. Bolt 84 also serves to rotatably mount gear 82 on bracket 14. The other end of link 83 is -pivotally connected to link 85 by bolt 81. Link 86 is pivotally connected at one end to link 85 and at the other end to a bolt identical with bolt 84. Bolt |90 carries a gear segment |9| identical with gear segment 82 which meshes with segment 11. A pin |92 performs the same function as pin 80.

With this above described arrangement, limited lateral movement of the cradle in the mount is permitted, allowing for small amounts of training movement without moving the entire mount.

The gun mount comprises a post 89, a bracket 90 welded thereto, and arms 9| and |80, arm 9| of which is pivotally connected to bracket 90 by bolt 92 and to arm 16 by bolt 93. Arm |80 is connected to bracket 90 by bolt |8| and to arm'15 by bolt |82. A link 95 is pivotally connected to A similar link connects bracket 90 and arm 15. Shaft 98, rotatably mounted in bearing portions 99, |00, |0|, and |02 of bracket 90, has keyed thereto a winding drum |03, to which is connected one end of a cable |04. The other end of the cable is connected by means of an eyebolt to a washer |05, which is slidably received in post 89 and constantly urged downwardly by spring |86. Gears |01 and |08 are keyed to shaft 98 to rotate therewith.l Shaft to which are fastened at the opposite ends thereof, idler gears of which only gear H vis shown. is freely rotatably and 20, drum |20 having .serrations mounted in bracket 90. Gear ||0 and its corresponding gear mesh respectively with racks lll and ||3 which in turn are fastened to arms 0| and |80. Vertical downward movement .of the gun and cradle about bolts 82 and |8| causes rotation of shaft 98'A because racks ||3 and ||4 rotate gear ||0 and its corresponding gear, which in'turn cause rotation of gears |01 and |08.`

Cable |04 is then wound on drum |03 compressing spring |06. The energy stored up in spring |06 returns the gun to normal position when the force urging the gun downwardly is relieved.

In order to hold the gun in a desired trained position, a locking mechanism is provided, which willnow beV described. Y ReferringY to Figures. 18 |2| thereon is keyed to shaft 98.' serrated locking members portions thereof into engagement with the serrated drum |20. Movement of the handle in the opposite direction allows spring |21 to draw the arms together, unlocking the arms from the drum and, consequently, unlocking the shaft to permit further training of the gun. Two of such locking mechanisms are provided, one on each side of drum |03 as shown in Figure 18.

Various modications may be made in the structure illustrated and described without departing from the spirit and scope of the invention. It is intended to be limited only by the appended claims.

We claim:

1. A back plate assembly for a rapid firing automatic machine gun comprising a back plate,

, an extension integral with said back plate, abutmentmeans freely slidably mounted on said extension and adapted to be connected to a support, recoil absorbing means mounted on said extension on one side of said abutment' means and counterrecoil absorbing means mounted on. said extension on the othei` side of said abutment means, and means for detachably connecting said back plate assembly to said gun whereby it may be separated from the gun as a unit.

2. In a machine gun a back plate assembly adapted to be readilyfattached to and separated from the machine gun as a unit, said assembly comprising a back plate, an extension integral with said back plate, a rimmed plug adjustably connected to said extension, a plate freely slidably mounted on said extension, a recoil spring between said plate and said gun, a counterrecoil spring between said plate and the rim of said plug, means for detachably connecting said plate to a gun support, said plug being adjustable to precompress said springs.

3. A gun mount comprising a hollow post member, a bracket integrally united with said post member, carriages pivotally connected to said bracket, a rack carried by each' of said carriages, cradle carrying arms pivotally connected to said carriages, a link pivotallyconnected to said bracket and said arms, a gear systemV mounted on said bracket to mesh with said rack and be actuated thereby, a drum rotatably mounted on said bracket in operative relation with said gear system, a cable attached to and adapted to be. wound upon said drum, a coil spring in said post member, means connected to said cable for engaging said spring to compress said spring upon rotation of said drum as a result of training said gun.

4. A gun mount comprising a pair of arms, a cradle mounted in said arms for vertical and lateral movement, a bracket having means thereon adapted to be received in a support, carriage memberspivotally connected to said bracket and to said arms, a link pivotally connected to said arms and said bracket and means carried by said bracket and actuated by movement of said cradle and arms for returning said cradle Yand arms to n a normal position.

5. A device as recited in claim 4 and further comprising means for locking said mount in a selected position.

6. A gun mount as recited in claim 4 and further comprising a shaft, a serrated drum keyed to said shaft, serrated levers pivotally mounted on said bracket, a spring for urging said serrated levers into inoperative position, and a cam member operative to urge saidv levers into engaging positiom 7. A back plate assembly for a rapid firing automatic gun comprising a back plate, an extension integral with said back plate, abutment means freely slidably mounted on said extension and adapted to be connected to-a support, a recoil absorbing spring mounted on said extension on one side of said abutment means and a counterrecoil absorbing spring mounted on said extension on the other side of said abutment means, said recoil and counterrecoil springs each having a natural period of vibration greater than the ring period of the gun, said springs being substantially identical and precompressed by such an amount that the resulting period of vibration of the combined gun and springs is so correlated with the firing period of the gun that the gun, when firing continuously, oscillates substantially between maximum recoil position and a point approximately halfway between maximum recoil position and battery position, and means for detachably connecting said back plate assembly to said gun and said abutment means to a support whereby said assembly may be separated from the gun as a unit without disturbing the adjustment of said springs.

8. A device for oatingly mounting a rapid firing automatic gun, comprising a cradle, a gun mounted for limited sliding movement in said cradle, a recoil spring adjacent the rear of the gun and between the gun and the cradle, and a counterrecoil spring adjacent the front of the gun and between the gun and the cradle, said m, springs being substantially identical and arranged substantially coaxial with the longitudinal axis of the gun, said springs further having a natural period of vibration greater than the firing period of the gun and a relatively large energy absorbing capacity, and being precompressed by lsuch an amount that the resulting period of vibration of ,the combined gun and springs is so correlated with the firing period of the gun that the gun, when ring continuously, oscillates substantially between maximum recoil position and a point approximately halfway between maximum recoil position and battery position.

WALTER G. MCNEILL. IRWIN GEO. BOEHM. 

